Merge lane base check: develop ba19748d4ed1

Merge lane base check: run the full gate on `develop` at `ba19748d4ed112ee3a54f7d7ecc0d138beefb63e` alone and report it certified or red: nothing had certified it since the last attempt. A red verdict files a fix task; it never holds the lane. Filed by the control plane (`app/merge_lane.py::_certify_idle`). How: run `python3 tools/merge_lane.py run` once. It takes this check's batch, gates that commit with the full gate in its sandbox and reports `certified` or `develop_red` itself. Never run the gate by hand: a hand-run green reports nothing, so no certificate is recorded (Task 6722).

develop ba19748d4ed1 is red: e2e/company-setup-self-service.spec.ts:173 expects 6 plan-limit rows and gets 5, failing again when run alone. Likely cause: 6440f2bb7 (Task 9648) removed the Active worktrees cap. Fix task #9707 is filed; nothing merged or ejected.